1. Field of the Invention
The present invention relates to a metal removing agent capable of removing metal clusters contained in fuel, and a metal removing filter having the metal removing agent therein capable of capturing metal clusters contained in fuel and removing the captured metal clusters from fuel with high efficiency.
2. Description of the Related Art
There is a fuel feed system for supplying fuel to an internal combustion engine. In general, the fuel feed system is comprised of a fuel tank and injectors. The fuel tank stores fuel such as diesel gasoline. Each of injectors injects the fuel supplied from the fuel tank into the cylinders of the internal combustion engine. Conventional techniques, for example, as disclosed in Japanese patent laid open publication No. JP 2006-105092 and Japanese patent laid open publication No. JP 2009-052562 have disclosed such a fuel feed system.
In general, each of injectors is composed mainly of a nozzle body and a needle. The nozzle body has an injection hole through which high pressure fuel is injected into a corresponding cylinder of the internal combustion engine. The injection hole is opened and closed by the needle when the needle moves upward and downward in the nozzle body. In more detail, such a type of the injector is further composed of a sliding unit of a cylinder shape, an inserting unit of a small cylindrical shape, and a pressure receiving unit. The sliding unit is moved in the nozzle body. The inserting unit of a small cylindrical shape is smaller in size than the sliding unit. The pressure receiving unit connects the inserting unit and the sliding unit together.
The nozzle body has a guide unit and a fuel accumulation chamber. The guide unit slidably supports the inserting unit. The fuel accumulation chamber is formed at the fuel injection side of the guide unit and temporarily accumulates fuel. The fuel accumulation chamber communicates with the inserting unit.
A high pressure fuel is supplied to the fuel accumulation chamber in order to inject the high pressure fuel into the corresponding cylinder of the internal combustion engine. The high pressure fuel is leaked through a gap between the sliding unit and the guide unit.
By the way, fuel for diesel engines generally contains a trace of metal components. Following Table 1 shows average amount of metal contained in the fuel used in forty-nine countries in the world.
TABLE 1MetalNaKCuFeMnNiZnCaTotalAverage0.0140.0160.0330.0170.0070.00040.0590.0430.19content (ppm)Ionization28.1Unknown23.111.2UnknownUnknown21.42.1—rate (%)*)*)Ionization rate (%): Percentage of Ion in average content (ppm)
Metal components such as Na and Zn contained in fuel are deposited and accumulated in the gap between the sliding unit and the guide unit in the injector having the structure described above. The accumulated metal components prevent the sliding unit in the injector from moving smoothly.
In order to avoid the above drawback, the conventional documents have proposed various improved techniques. For example, Japanese utility model laid open publication No. H03-59012 discloses a filter having chelating resin, and Japanese patent laid open publication No. JP 2006-105092 and Japanese patent laid open publication No. JP 2009-052562 have disclosed the fuel supply system equipped with a metal ion exchange means.
However, it is difficult for the conventional techniques to adequately prevent metal components contained in fuel from being deposited on and accumulated in the gap between the sliding nit and the guide unit of the injector.